The present invention relates generally to electrical discharge machines (EDM) and in particular to an electrode holder for such machines.
Electrical Discharge Machines (EDM) make use of specially shaped electrodes to cut complex surfaces into metal molds or the like. The surface cut in the workpiece mirrors the shape of the electrode which is typically machined on a numerically controlled milling machine or the like and then transferred to the EDM machine.
In order to obtain precise registration between the surface of the electrode cut on the milling machine and the work piece held in the EDM machine, it is known to attach special chucks to each of the these machines in predefined locations with respect to the milling cutter on the milling machine and the workpiece on the EDM machine. Once the chucks are located, the electrode may be transferred freely between the milling machine and the EDM machine while maintaining a precise registration.
Chucks and electrode holders for this purpose are available from the 3R Company, Midwest Technical Center, Elk Grove Village, Ill. These chucks and electrode holders are particularly designed to allow rapid automatic changing of electrodes on the milling and EDM machine (tool changing).
The electrode holders that are provide with such systems, which may provide a channel having inwardly directed set screws to grip the surface of the electrode are not well suited for some types of electrodes, in particular, for relatively thin or cylindrical graphite electrodes. Special fixtures may have to be prepared to hold these electrodes and/or the electrodes may need to be glued in place using epoxy or the like. This latter gluing step can make reuse of the relatively expensive electrode holders difficult.